The invention relates to a scan region determining apparatus (12) for determining a scan region of a subject to be scanned by a scanning system (10) like a computed tomography system. A spatial transformation defining a registration of an overview image and a template image with respect to each other is determined, wherein initially the overview image and the template image are registered by using an element position indicator being indicative of a position of an element of the subject with respect to the overview image. A template scan region is defined with respect to the template image, wherein a final scan region is determined by projecting the template scan region onto the overview image by using the determined spatial transformation. The registration and thus the determination of the spatial transformation are very robust, which improves the quality of determining the final scan region.
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1. A scan region determining apparatus for determining a scan region of a subject to be scanned by a scanning system, the scan region determining apparatus comprising: an overview image providing unit configured to provide an overview image of a subject, an element position indicator determination unit configured to determine an intermediate scan region being indicative of a position of an element of the subject to be scanned, wherein the element position indicator determination unit is adapted to determine the intermediate scan region with respect to and based on the overview image, wherein the intermediate scan region is an intermediate scan region plan box, a template image providing unit configured to provide a template image of a template subject, which corresponds to the subject to be scanned, and for providing a template scan region including a template element, which corresponds to the element of the subject to be scanned, wherein the template image providing unit is adapted to provide a template scan region, which is defined with respect to the template image, wherein the template scan is a template scan region plan box, spatial transformation determination unit configured to determine a spatial transformation defining a registration of the overview image and the template image with respect to each other, wherein initially the overview image and the template image are registered by using the determined intermediate scan region being indicative of the position of the element of the subject to be scanned with respect to the overview image, a scan region determination unit configured to determine a final scan region by projecting the template scan region onto the overview image by using the determined spatial transformation, wherein the final scan region is a final scan region plan box.
A scan region determining apparatus automatically identifies a scan region on a subject for a scanning system (like CT). It uses an overview image of the subject, finds an approximate region of interest ("intermediate scan region plan box") containing the element to be scanned within the overview image. The system also has a template image of a similar subject with a known scan region ("template scan region plan box") around the corresponding element. It registers the overview and template images, using the intermediate scan region to aid the registration process. Finally, it projects the template scan region onto the overview image using the registration transformation, defining the final scan region plan box.
2. The scan region determining apparatus as defined in claim 1 , wherein the element position indicator determination unit is adapted to determine at least a center of the element in the overview image as the element position indicator.
The scan region determining apparatus from the previous description determines the intermediate scan region by identifying the *center* of the element of interest in the overview image. The element's center is used as the element position indicator. This simplifies the initial registration process between the overview and template images by providing a specific point of correspondence.
3. The scan region determining apparatus as defined in claim 2 , wherein the spatial transformation determination unit is adapted to initially register the overview image and the template image with respect to each other by centering the template image on the determined center of the element in the overview image.
Building on the previous description of the scan region determining apparatus identifying the center of the element, the registration process between the overview and template images starts by aligning the *template image center* with the *identified element center* in the overview image. This initial alignment provides a good starting point for a more refined spatial transformation determination.
4. The scan region determining apparatus as defined in claim 1 , wherein the element position indicator determination unit is adapted to use a Viola-Jones algorithm for determining the intermediate scan region.
The scan region determining apparatus from the initial description uses a Viola-Jones algorithm to locate the intermediate scan region of the element to be scanned within the overview image. This algorithm is a fast and robust object detection method, suitable for quickly finding the approximate location of the element of interest.
5. The scan region determining apparatus as defined in claim 1 , wherein the element position indicator determination unit is adapted to: use an element position indicator determination algorithm for determining the element position indicator, provide element position indicator determination rules for selecting a most likely element position indicator, if the element position indicator determination algorithm revealed several possible element position indicators, and apply the element position indicator determination rules to the determined several possible element position indicators for determining the element position indicator to be used by the spatial transformation unit.
The scan region determining apparatus, as previously described, uses an element position indicator determination algorithm to find the element. If this algorithm finds multiple possible locations, it applies pre-defined rules to pick the most likely location. These rules help resolve ambiguities and ensure that the best possible element position is used for subsequent spatial transformation calculations.
6. The scan region determining apparatus as defined in claim 1 , wherein the spatial transformation determination unit is adapted to apply an intensity based registration algorithm to the overview image and the template image for determining the spatial transformation, wherein the image intensity based registration algorithm is initialized based on the determined intermediate scan region being indicative of the position of the element of the subject to be scanned with respect to the overview image.
The scan region determining apparatus from the first description refines the registration between the overview and template images using an intensity-based image registration algorithm. This algorithm directly compares the pixel intensities in the two images to find the best spatial transformation. To improve robustness and speed, the registration is initialized based on the initial intermediate scan region, focusing the search for the best transformation.
7. The scan region determining apparatus as defined in claim 1 , wherein the template image providing unit is adapted to provide a position of a template indicator element in the template image, wherein the template scan region is defined with respect to the position of the template indicator element, and wherein the scan region determination unit is adapted to project the template scan region onto the overview image by transforming the position of the template indicator element by using the determined spatial transformation and determining the template scan region on the overview image based on the transformed position of the template indicator element.
The scan region determining apparatus utilizes a template image with a defined "template indicator element" and its position. The template scan region is defined relative to this template indicator element. During scan region determination, the apparatus projects the template scan region onto the overview image by transforming the position of the template indicator element using the calculated spatial transformation, and the template scan region is then determined around this transformed position on the overview image.
8. The scan region determining apparatus as defined in claim 1 , further comprising: a training images providing unit for providing training images of a subject comprising an element and for providing training scan regions including the element of the subject in the training images, a training unit for training the element position indicator determination unit based on the provided training images and training scan regions.
The scan region determining apparatus from the original description also includes a training component. It uses training images of subjects containing the element of interest, along with corresponding training scan regions around those elements. The element position indicator determination unit is trained using this data to improve its accuracy in identifying the element's location in new overview images.
9. A scan region determining method for determining a scan region of a subject to be scanned by a scanning system, the scan region determining method comprising: providing an overview image of a subject by an overview image providing unit, determining an intermediate scan region being indicative of a position of an element of the subject to be scanned by an element position indicator determination unit, wherein the element position indicator determination unit determines the intermediate scan region with respect to and based on the overview image, wherein the element position indicator is an intermediate scan region plan box, providing a template image of a template subject, which corresponds to the subject to be scanned, and providing a template scan region including a template element, which corresponds to the element of the subject to be scanned, by a template image providing unit, wherein the template image providing unit provides a template scan region, which is defined with respect to the template image, wherein the template scan is a template scan region plan box, determining a spatial transformation defining a registration of the overview image and the template image with respect to each other by a spatial transformation determination unit, wherein initially the overview image and the template image are registered by using the determined intermediate scan region being indicative of the position of the element of the subject to be scanned with respect to the overview image, determining a final scan region by projecting the template scan region onto the overview image by using the determined spatial transformation by a scan region determination unit, wherein the final scan region is a final scan region plan box.
A scan region determining method automatically identifies a scan region on a subject for a scanning system (like CT). It involves acquiring an overview image, and then finding an approximate region of interest ("intermediate scan region plan box") in that image which contains an element to be scanned. The method also uses a template image of a similar subject, with a pre-defined scan region ("template scan region plan box") around the element to be scanned in the template. The overview and template images are registered using spatial transformation and the intermediate scan region helps in the registration process. Finally, it projects the template scan region onto the overview image using the registration transformation, defining the final scan region plan box.
10. The scan region determining method as defined in claim 9 , further comprising: determining at least a center of the element in the overview image as the element position indicator.
The scan region determining method, as described previously, refines the element location process by specifically identifying the *center* of the element in the overview image. This center point is then used as a more precise element position indicator for subsequent steps.
11. The scan region determining method as defined in claim 10 , further comprising: registering the overview image and the template image with respect to each other by centering the template image on the determined center of the element in the overview image.
This scan region determining method builds on the step of determining the center of the element. The overview and template images are initially registered by aligning (centering) the template image on the determined center of the element in the overview image. This provides a good starting alignment for a more accurate registration.
12. The scan region determining method as defined in claim 9 , further comprising: employing a Viola-Jones algorithm for determining the intermediate scan region.
The scan region determining method, as previously described, utilizes the Viola-Jones algorithm to locate the intermediate scan region within the overview image. This algorithm efficiently detects the presence and location of the element in the overview image.
13. The scan region determining method as defined in claim 9 , further comprising: using an element position indicator determination algorithm for determining an element position indicator, providing element position indicator determination rules for selecting a most likely element position indicator, if the element position indicator determination algorithm revealed several possible element position indicators, and applying the element position indicator determination rules to the determined several possible element position indicators for determining the element position indicator to be used by a spatial transformation unit.
In the scan region determining method, the location of the element is found by using a detection algorithm. If the algorithm finds multiple possible locations for the element, pre-defined rules are applied to determine the most likely location. This selection ensures that the best position is used for spatial transformation calculations.
14. The scan region determining method as defined in claim 9 , further comprising: applying an intensity based registration algorithm to the overview image and the template image for determining the spatial transformation, wherein the image intensity based registration algorithm is initialized based on the determined intermediate scan region being indicative of the position of the element of the subject to be scanned with respect to the overview image.
In the described scan region determining method, the registration between the overview and template images is refined using an intensity-based registration algorithm. The initial intermediate scan region (location of the element) in the overview image is used to initialize this algorithm, which improves the speed and accuracy of the spatial transformation determination.
15. The scan region determining method as defined in claim 9 , further comprising: providing a position of a template indicator element in the template image, wherein the template scan region is defined with respect to the position of the template indicator element; projecting the template scan region onto the overview image by transforming the position of the template indicator element by using the determined spatial transformation; and determining the template scan region on the overview image based on the transformed position of the template indicator element.
The scan region determining method uses a template image containing a "template indicator element" and its position. The template scan region is defined relative to the position of the template indicator element within the template image. The method projects the template scan region onto the overview image by transforming the position of the template indicator element using the calculated spatial transformation, and then uses the transformed position to define the template scan region on the overview image.
16. The scan region determining method as defined in claim 9 , further comprising: providing training images of a subject comprising an element and for providing training scan regions including the element of the subject in the training images, and training the element position indicator determination unit based on the provided training images and training scan regions.
This scan region determining method includes a training step. Training images containing the element to be scanned, along with corresponding training scan regions, are used to train the element position indicator determination unit. This training improves the accuracy of the element detection process in new overview images.
17. A non-transitory computer readable medium encoded with computer executable instructions for determining a scan region of a subject to be scanned by a scanning system which when executed by a processor of a computer causes the computer to: create an intermediate scan region plan box in an overview image; retrieve a template image having a template plan box; register the overview image and the template image based on the intermediate scan region plan box, creating a spatial transformation there between; and determine a final scan plan box in the overview image by projecting the template plan box onto the overview image using the spatial transformation.
A non-transitory computer readable medium contains instructions to determine a scan region on a subject's image. The instructions cause the computer to first find an approximate area ("intermediate scan region plan box") in an overview image; retrieve a template image which also has a defined area ("template plan box"); register the overview image and template image, based on the intermediate scan region, creating a spatial transformation; and determine a final scan plan box in the overview image by projecting the template plan box from the template onto the overview image using the spatial transformation.
18. The non-transitory computer readable medium of claim 17 , wherein the instructions further causes the computer to: determine at least a center of the element in the overview image as the element position indicator.
This invention relates to computer vision and image processing, specifically for identifying and locating elements within an overview image. The problem addressed is accurately determining the position of an element within a larger image, which is crucial for applications such as object detection, augmented reality, and automated analysis. The solution involves a non-transitory computer-readable medium containing instructions that, when executed by a computer, perform a method to process an overview image. The method includes capturing the overview image containing at least one element, analyzing the image to identify the element, and determining the position of the element within the image. The position is specifically identified by calculating the center of the element in the overview image, which serves as the element position indicator. This center-based positioning provides a precise and standardized way to locate the element, improving accuracy in subsequent processing steps. The method may also involve additional steps such as generating a detailed image of the element or performing further analysis based on the determined position. The invention enhances the reliability of element detection and positioning in various imaging applications.
19. The non-transitory computer readable medium of claim 18 , wherein the instructions further causes the computer to: initially register the overview image and the template image with respect to each other by centering the template image on the determined center of the element in the overview image.
The computer readable medium instructions described earlier include instructions to initially register the overview and template images by centering the template image on the identified center of the element in the overview image.
20. The non-transitory computer readable medium of claim 17 , wherein the instructions further causes the computer to: apply an intensity based registration algorithm to the overview image and the template image to determine the spatial transformation, wherein the image intensity based registration algorithm is initialized based on the determined intermediate scan region being indicative of the position of the element of the subject to be scanned with respect to the overview image.
The computer readable medium, as described before, holds further instructions to apply an intensity-based registration algorithm to the overview and template images. This algorithm is initialized with the information from the determined intermediate scan region to improve the process of spatial transformation.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
February 26, 2014
June 20, 2017
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